Numerous fern impressions also are found in shale beds above the Herrin (No. 6) Coal along the Middle Branch of Copperas Creek, six miles west of Glasford. Other specimens may be found in these beds elsewhere in the area.
McDonough County
In some of the small underground mines near Colchester, the shale overlying the Colchester (No. 2) Coal contains ironstone concretions similar to those from northeastern Illinois. More than 50 species of plant fossils have been reported, but they were collected many years ago from spoil heaps at the mines. Beds of the same age crop out widely in other localities in western Illinois and may contain plant fossils.
Plate 4
Sphenopteris ⅗× Linopteris ⅗× Neuropteris ½× Odontopteris ⅗× Cycopteris ½× Alethopteris ⅗× Alethopteris ⅗× Odontopteris ½× Alethopteris ⅗×
Vermilion County
In outcrops about three miles below Georgetown on the Little Vermilion River, a number of fossil plant species and one insect species have been collected from shales overlying the Herrin (No. 6) Coal, locally called the Grape Creek Coal. The fossils occur in concretions much like those from Mazon Creek.
An occasional stem replacement or impression is found in the concretionary shale above the No. 7 Coal in the strip mine area west of Hillery. In fact, isolated fragmentary plant specimens are fairly common in the Danville mining area, but no especially productive localities have come to light.